A fermionic bath induced antibunching and coherence in Mollow spectra

In this work, we have derived the modified Bloch equation from the generalized master equation due to the fermionic bath where one needs to consider Grassmann algebra to obtain the similar mathematical structure of the reduced system dynamics, as in the case of a bosonic bath. There is an enhancement of antibunching in the photon emission with an increase in effective temperature. This is in principle a manifestation of the antisymmetric two-particle dynamic anticorrelation in the fermionic bath with a defined chemical potential characterized by the forbidden overlapping. This is evident from the modified fluctuation–dissipation relation. We have compared it thoroughly with an experimental result in the temperature dependent emission characteristics within an environment of quantum dots in a Hanburry-Brown–Twiss set-up. For the fermionic bath, an effective temperature assisted coherence phenomenon is induced in the system dynamics, which is reflected in the resonance fluorescence spectrum with the variation of chemical potential. In the Mollow's absorption spectra, when the Rabi frequency is sufficiently low, the side peaks appear as chemical potential induced coherence phenomenon rather than the traditional field induced one. The subsequent gain in the probe wave is evidently of thermal origin, where the energy is fully supplied by the fermionic bath at non-zero temperatures. This is not possible for a bosonic bath—an example of the extraction of coherence from the fermionic bath. (paper)